Objective To analyze the mechanism of action of seaweed-kunbu in the treatment of breast cancer through network pharmacology.

Methods The active ingredients and their targets of seaweed-kunbu were retrieved through the TCMSP database. Relevant targets for breast cancer were obtained through the GeneCards and OMIM databases, and "drug-disease target" network diagram was constructed using Cytoscape software. Protein-protein interaction (PPI) network analysis was performed using the String platform. Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed using R language. Molecular docking technology was used to verify the binding ability of key compounds to targets, and functional verification was carried out through in vitro experiments.

Results A total of 11 effective compounds were obtained from seaweed-kunbu in this study, among which 10 were related to breast cancer. There were 150 highly relevant intersecting targets between seaweed-kunbu and breast cancer, and 10 core genes including Serine/threonine kinase 1 (AKT1), p53 tumor protein (TP53), tumor necrosis factor (TNF), interleukin6 (IL6), vascular endothelial growth factor A (VEGFA), JUN, caspase 3 (CASP3), interleukin1B (IL1B), MYC and human epidermal growth factor receptor (EGFR) were screened out. GO analysis indicated that these compounds may be involved in biological processes such as signal transduction, apoptosis, cell proliferation, and inflammatory response. KEGG pathway analysis showed that the main enriched signaling pathways were PI3K/Akt, MAPK and TNF. Molecular docking and in vitro experimental results demonstrated that fucosterol, the main chemical component of seaweed-kunbu, had an antiproliferative effect on triple-negative breast cancer BT-549 cells.

Conclusion Seaweed-kunbu may treat breast cancer through multiple targets and pathways, and its main chemical component fucosterol can effectively inhibit the proliferation activity of BT-549 cells.